Wind Drivetrain Bearing Reliability

Click here to load reader

download Wind Drivetrain Bearing Reliability

of 43

  • date post

    19-Aug-2014
  • Category

    Engineering

  • view

    359
  • download

    2

Embed Size (px)

description

 

Transcript of Wind Drivetrain Bearing Reliability

  • Wind Drivetrain Bearing Reliability
  • Before We Start This webinar will be available at www.windpowerengineering.com & email Q&A at the end of the presentation Hashtag for this webinar: #WindWebinar
  • Moderator Presenter Paul Dvorak Windpower Engineering & Development Rick Brooks The Timken Company
  • Wind Drivetrain Bearing Reliability Presented by The Timken Co. Richard Brooks, Mgr. Wind North America
  • WIND TURBINE DRIVETRAIN - COMMON BEARING DAMAGE Generator Bearings Gearbox High Speed Bearings Gearbox Planet Bearings Main Shaft Bearings
  • FINANCIAL IMPACT - WIND DRIVETRAIN BEARING DAMAGE $0 $500,000 Low High T O T A L R E P A I R C O S T Frequency of Occurrence Generator Bearings Gearbox High Speed Bearings Gearbox Planet Bearings Main Shaft Bearings $$$ $
  • UP TOWER VS. DOWN TOWER REPAIRS Up Tower Down Tower Crane Costs +++ --- Self Perform ++ - Clean Environment - ++ Load Test --- ++ Per Event Cost ~$10-$20k ~$250k-$500k
  • Two TS TDI and CRB Ultrawind Two SRBs Single SRB WIND TURBINE MAIN SHAFT MOUNTS
  • Hub Weight Wind Thrust Torque Overturning Moments Spherical Roller (SRB) Main Bearing MAIN SHAFT APPLICATION REVIEW-3 POINT MOUNT SRB
  • MAIN SHAFT SRB OBSERVED DAMAGE MODES: LOW SPEED AND HIGH THRUST COMBINED= Micropitting
  • MAIN SHAFT SRB OBSERVED DAMAGE MODES: LOW SPEED AND HIGH THRUST COMBINED= Edge Loading
  • MAIN SHAFT SRB OBSERVED DAMAGE MODES: LOW SPEED AND HIGH THRUST COMBINED= Single Piece Cage Damage
  • MAIN SHAFT SRB OBSERVED DAMAGE MODES: LOW SPEED AND HIGH THRUST COMBINED= Debris Damage
  • MAIN SHAFT SRB ENHANCEMENTS Enhanced Geometry Reduce edge loading Improves roller/race contact Decreases roller stresses
  • MAIN SHAFT SRB ENHANCEMENTS Surface Finish Reduced asperity contact and stress Higher surface film, lower torque Reduce friction and wear
  • MAIN SHAFT SRB ENHANCEMENTS Two Piece Cage: Lower operating forces/stress
  • MAIN SHAFT SRB ENHANCEMENTS Wear Resistant DLC Coatings Mitigate surface wear damaged Increase fatigue life Increase debris resistance
  • TECHNOLOGY DESCRIPTION BENEFITS Roller Finishing Low Roughness, Isotropic Finish Reduced Asperity Contact & Stress Roller Coating WC/aC:H Coating 1 m thick Increased Wear Resistance, Increased Fatigue Life, Increased Debris Resistance. Internal Geometry Roller/IR Conformity Decreases Roller Stress, Reduces Potential Roller Skew Creates Favorable Traction Split Cage Two-Piece Machined Brass Cage Lowers Possible Operating Forces TIMKEN WEAR-RESISTANT SRB Wear Resistant SRB
  • Grease / Debris Race condition RESULTS OF TIMKEN WEAR RESISTANT SRBS AFTER 4 YEARS OPERATION
  • MAIN SHAFT BEARING HEALTH- OTHER FACTORS Condition Monitoring Statistical analysis and trending of bearing temperatures Vibration or Shock Pulse analysis Lubrication Practices Variation in manual greasing practices (amount & frequency) Value of Auto-Lubrication systems Grease Selection Investigate characteristics of current grease and alternatives Grease Flush Designed to extend the life of bearings in early stages of wear 20
  • High Speed & Intermediate shafts: High occurrence Rate Axial cracks on Inners Planetary positions: Medium occurrence Rate Debris & load damage WIND GEARBOX BEARINGS Planet Carrier & Low Speed Positions: Low occurrence Rate Thrust damage
  • SRB CRB TRB Integrated CRB Integrated TRB PLANET BEARING ARRANGEMENTS - DEVELOPMENT
  • PLANET BEARING - OBSERVED DAMAGE MODES 23 Non-Integrated Integrated TRB Debris damage Creeping Outer Debris damage CRB Debris damage Thrust load Heavy / Uneven loading Smearing Creeping outer Debris damage Thrust Loading Smearing
  • PLANET BEARING ENHANCEMENTS SRB: Replace with new design CRB: Case carburized DLC coating Modified controlled clearances Redesign as TRB or integrated TRB: Case carburized Redesign as integrated
  • CRB CRB + ball bearing HIGH SPEED AND INTERMEDIATE COMMON GEARBOX BEARING ARRANGEMENTS Non-locating Position Locating Position Options Double TRB Single TRB
  • HIGH SPEED & INTERMEDIATE BEARINGS OBSERVED DAMAGE MODES I R r R r F 1. Smearing 3. White Etch Area Axial Cracking / Flaking 2. Inclusion Related: Axial Cracking / Spalling
  • ROLLER SLIDING / SMEARING IN CRB IR r R I R R r Outer Race Inner Race Cage Roller D - roller sliding increases outside the load zone C load zone exit most of the traction forces are lost beyond this point F B - traction forces restore roller velocity to pure rolling motion in load zone A smearing as roller accelerates entering the load zone Load distribution in load zone
  • INCLUSION RELATED AXIAL CRACKING Caused by non-ferrous contaminants in the steel Commonly manifests as White Etch Butterflies Material transforms in the area of the inclusion Crack forms and prorogates to the surface or spalls
  • WHITE ETCH AREAS CRACKS 1. Hoop Stress from original Press Fit on shaft 2. Tensile stresses from roller sliding & skewing 3. Dynamic conditions begin the subsurface transformation 4. Crack forms in the hard & brittle transformed area 5. Crack propagates to the surface
  • WHITE ETCH AREAS CRACKS 2. Tensile stresses from roller sliding & skewing IR r R r F
  • WHITE ETCH AREAS CRACKS 3. 3. Dynamic conditions begin the subsurface transformation
  • WHITE ETCH AREAS CRACKS Dynamic Event Dynamic Event Normal Load Normal Load Plastic Deformation Transformation Plastic Deformation Transformation 4. 4. Crack forms in the hard & brittle transformed area
  • WHITE ETCH AREAS CRACKS 5. 5. Crack propagates to the surface
  • BEARING ENHANCEMENTS - HIGH SPEED & INTERMEDIATE Enhancement White Etch Inclusions Smearing Steel Cleanliness + +++ Black Oxide + (early stages) ++ (early stages) DLC Coatings + +++ Case Carburized +++ ++
  • 0 1 2 3 4 CompletedSmearingTestCycles Smeared during first cycle ENGINEERED SURFACE: PERFORMANCE COMPARISON Ground Honed/ES20 Honed/ES20/Black Oxide Wear-Resistant
  • ENGINEERED SURFACES (COATINGS & TREATMENTS) Black Oxide Surfaces Black oxide is a conversion treatment: Metallic parts are put into a hot bath containing oxidizing salts Steel reacts with the oxidizing salts to form a thin layer of magnetite on the surface (Fe3O4). Black oxide is a sacrificial surface Benefits: Aesthetics Corrosion prevention Run-in and/or performance improvement Prevents mild adhesive wear damage Improve rolling contact fatigue life DLC Coated Surfaces DLC is a hard coating: Tungsten carbide incorporating an amorphous hydrocarbon composite. Applied with a Physical Vapor Deposition process in a vacuum chamber. Benefits: Improve rolling contact fatigue life. Mitigate life limiting wear damaged caused by metal adhesion. Increased fatigue Life Increased debris resistance Prevent scuffing or smearing damage (Timken Wear Resistant coating)
  • Inner Race Subsurface Condition Roller coating intact RESULTS OF TIMKEN CRB (CASE CARBURIZED AND WEAR RESISTANT) AFTER 18 MONTHS
  • GEARBOX BEARING HEALTH OTHER FACTORS Condition Monitoring Oil analysis programs and Online oil monitoring systems Vibration or Shock Pulse analysis Oil Selection Anti-Foaming Additives / Properties Oil System Accessories Moisture removal systems Oil filtration systems Quality Oil Changes Frequency based on oil monitoring condition Vendor oil change features 38
  • GENERATOR BEARING OBSERVED DAMAGE MODES Electrical Fluting Inadequate Lubrication